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    <title>odeoptions</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : February 1998</div>
    <p>
      <b>odeoptions</b> -  set options for ode solvers</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>odeoptions()  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    This function interactively displays a command which
    should be executed to set various options of ode solvers.
    The global variable <tt>
        <b>%ODEOPTIONS</b>
      </tt> sets the options.</p>
    <p>
    CAUTION: the <tt>
        <b>ode</b>
      </tt> function checks if this variable
    exists and in this case it uses it. For using default
    values you should clear this variable. Note that <tt>
        <b>odeoptions</b>
      </tt>
    does not create this variable. To create it you must execute
    the command line displayed by <tt>
        <b>odeoptions</b>
      </tt>.</p>
    <p>
    The variable <tt>
        <b>%ODEOPTIONS</b>
      </tt> is a vector with the following elements:</p>
    <pre>

[itask,tcrit,h0,hmax,hmin,jactyp,mxstep,maxordn,maxords,ixpr,ml,mu]
   
    </pre>
    <p>
    The default value is:</p>
    <pre>

[1,0,0,%inf,0,2,500,12,5,0,-1,-1]
   
    </pre>
    <p>
    The meaning of the elements is described below.</p>
    <p>
      <tt>
        <b>itask</b>
      </tt>
     1 : normal computation at specified times
     2 : computation at mesh points (given in first row of output of <tt>
        <b>ode</b>
      </tt>)
     3 : one step at one internal mesh point and return
     4 : normal computation without overshooting <tt>
        <b>tcrit</b>
      </tt>
     5 : one step, without passing <tt>
        <b>tcrit</b>
      </tt>, and return</p>
    <p>
      <tt>
        <b>tcrit</b>
      </tt>
      assumes <tt>
        <b>itask</b>
      </tt> equals 4 or 5, described above</p>
    <p>
      <tt>
        <b>h0</b>
      </tt>
      first step tried</p>
    <p>
      <tt>
        <b>hmax</b>
      </tt>
      max step size</p>
    <p>
      <tt>
        <b>hmin</b>
      </tt>
      min step size</p>
    <p>
      <tt>
        <b>jactype</b>
      </tt>
     0 : functional iterations, no jacobian used (<tt>
        <b>"adams"</b>
      </tt> or
         <tt>
        <b>"stiff"</b>
      </tt> only)
     1 : user-supplied full jacobian
     2 : internally generated full jacobian
     3 : internally generated diagonal jacobian (<tt>
        <b>"adams"</b>
      </tt> or 
         <tt>
        <b>"stiff"</b>
      </tt> only)
     4 : user-supplied banded jacobian (see <tt>
        <b>ml</b>
      </tt> and <tt>
        <b>mu</b>
      </tt> below)
     5 : internally generated banded jacobian (<tt>
        <b>see</b>
      </tt> ml and <tt>
        <b>mu</b>
      </tt> below)</p>
    <p>
      <tt>
        <b>maxordn</b>
      </tt> 
     maximum non-stiff order allowed, at most 12</p>
    <p>
      <tt>
        <b>maxords</b>
      </tt>
     maximum stiff order allowed, at most 5</p>
    <p>
      <tt>
        <b>ixpr</b>
      </tt> 
     print level, 0 or 1</p>
    <p>
      <tt>
        <b>ml</b>
      </tt>,<tt>
        <b>mu</b>
      </tt>
     If <tt>
        <b>jactype</b>
      </tt> equals 4 or 5, <tt>
        <b>ml</b>
      </tt> and <tt>
        <b>mu</b>
      </tt> are the lower
     and upper half-bandwidths of the banded jacobian: the band is the
     i,j's with i-ml &lt;= j &lt;= ny-1.
     If <tt>
        <b>jactype</b>
      </tt> equals 4 the jacobian function must return
     a matrix J which is  ml+mu+1 x ny (where ny=dim of y in ydot=f(t,y))
     such that column 1 of J is made of mu zeros followed by
     df1/dy1, df2/dy1, df3/dy1, ... (1+ml possibly non-zero entries)
     column 2 is made of mu-1 zeros followed by df1/dx2, df2/dx2, etc</p>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="ode.htm">
        <tt>
          <b>ode</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
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